.0.18 Micron Sidewall (spacer) Dry Etching Process Development And Optimization

This thesis mainly focuses on the development of dry etching process for 0.18um Spacer. Improving previous dry etching process, we successfully developed new etch process by taking use of our company's current machines and local resource.According to 0.18um Spacer etch have small foot in dense line, we discovered some problems basing on existing machines and process technology. The main problems are the low Etch Rate Selectivity causing Over etch on the top Oxide of Gate and the low Etch Rate Uniformity causing Spacer profile tapered and CD smaller. So we do improvement mainly in three approaches as follows.Firstly, we use DPS plus tool instead of DPS tool in order to increase new etching gas SF₆. Afterwards we improve Etch Rate Selectivity, Uniformity and also improve profile, CD of Spacer, but on the Gate, some Nitride remained.Secondly, we changed back side helium pressure to improve Etch Rate Uniformity. Furthermore we observed the thickness of Oxide remained, but on the Gate, some Nitride still remained.Finally, by adjust the gas flow ratio of CF4 and CHF3, we developed some new etch recipes which has high Etch Rate Uniformity and Selectivity of Oxide to Nitride so that no Nitride remained on the Gate. From design of experiment(DOE) data, we got the process boundary for the Spacer etch on DPS plus. We did electrical tests and the results confirmed that the new process developed in this thesis can meet the product requirements.